• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.85-93
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• 2019

The objective of this study is to assess the environmental effect of the reclaimed land drainage method using oyster shell through the Life cycle $CO_2$ assessment, and to evaluate the applicability in South Korea. In this Study, the life cycle $CO_2$ emissions of oyster shell (OS) and crushed stone (CS, as avoided product) were assessed and compared. The Life Cycle Assessment method was used for quantitative evaluation of direct or indirect environmental effects of OS recycling. $CO_2$ was selected as the evaluation target material, and the scope of assessment includes the acquisition of materials, processing, transportation, construction phases. Compared to using CS, 77.0% of $CO_2$ emissions in acquisition and processing, 47.0% in transportation and 6.5% in construction phase were reduced, respectively by using of OS. The maximum transportation distance of OS was estimated according to transportation distance of CS. OS has environmental advantages than CS within about 26 - 101 km from the source. OS was found to be applicable to reclaimed lands up to 810 ha, 3,910 ha from Tongyeong and Yeosu, respectively. In addition, the amount of OS that could be used as drainage material for reclaimed land was much higher than annual OS production of South Korea. Therefore, it is considered that OS is sufficient to be used as drainage material for reclaimed land in South Korea.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.1-6
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• 1994

Many vehicle routing methods have been suggested, which minimize the routing distances of vehicles to reduce the total transportation cost. In describing a distribution network, we have stated that it is basically a system or a set of locations that, receive or store material plus the routes that connect these locations. Whether the network is spread over some geographic region or is whitin a single facility, the definition remains the same. Implicit in this definition, however, is that both the locations and the transportation between these locations must be considered in any decisions regarding the design of the operation of the overall network. The purpose of this paper is optimal layout using transportation quantity and distance in the total system operation. And we minimize the sum of load-carrier costs and spur costs in this flow network.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.788-793
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• 2001

Finite element analysis was carried out to investigate the integrity and reliability of boiler module during sea transportation. The boiler module was supported by steel structure to relieve the instantaneous shock from oceanic wave and its primary parts were strengthened with several reinforcements. Finned tube walls which were used in the furnace wall were assumed as orthotropic plates having equivalent material properties. The bank tubes were also equivalently modeled in accordance with ASME B31.1 for the convenience of finite element modeling. The calculation results were compared with the yield stress of the material. In particular, the bank tube stress, which was evaluated by converting the calculated stresses in equivalent tubes into those in original tubes by using the ratio of diameter, was also examined with yield stress.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.236-240
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• 2012

Limiting thermal exposure time using rapid thermal processing(RTP) has emerged as promising simplified process for manufacturing of solar cell in a continuous way. This paper reports the simplification of co-firing using RTP. Actual temperature profile for co-firing after screen printing is a key issue for high-quality metal-semiconductor contact. The plateau time during the firing process were varied at $450^{\circ}C$ for 10~16 sec. Glass frit in Ag paste etch anti-reflection layer with plateau time. Glass frit in Ag paste is important for the Ag/Si contact formation and performances of crystalline Si solar cell. We achieved 17.14% efficiency with optimum conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.529-532
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• 2003

In this paper, the discharge characteristics of silent discharge chamber with 2mm and 3mm gap spacings were investigated. Dielectric of $Al_2O_3$ was embedded in the cylindrical type of discharge chamber. It was known that V-I and P-V characteristics depend strongly on the charge transportation characteristics, and in the low frequency silent discharge mode of operation, discharge voltage was always sustained to Vd, irrespective of applied voltage.

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.7-10
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• 2013

Metal oxides are known as stable materials during a thermal treatment. However, some oxides are readily evaporated at high temperatures. A voloxidation process is a head-end process for a pyroprocessing dealing with spent nuclear fuels (SF). In SFs, fission productions are in the form of oxides and some of them would be evaporated during the voloxidation process. Therefore, it is of importance to analyse the vapor pressures of metal oxides so that the material flows throughout the pyroprocessing could be estimated. In this work, vapor pressures of relevant metal oxides were calculated and presented to draw a baseline on the material flow of the pyroprocessing.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.2
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• pp.25-34
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• 2020

As leakage in nuclear power plants could cause a variety of problems, it is very critical to monitor leakage from the safety point of view. Accordingly, a new type of leak detection system is currently being developed and flow characteristics of the sampling and transportation system are investigated by using numerical analysis as a part of the development process in this study. The results showed that the steam mass fraction varied according to the effect of the gap between the insulation and piping component, transportation velocity, and material properties of porous media during the sampling and transportation process. The results of this study should be useful for understanding flow characteristics of the sampling and transportation system and its design and application.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.94-109
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• 1998

The purpose of this study was to evaluate the effect of materials and sizes of files on canal transportation in a curved canal. The stress and the strain energy of files of two kinds of materials (stainless steel and NiTi) and five sizes (No. 20, 25, 30, 35 and 40) in a curved canal were analyzed by a finite element program, NASTRAN. Curved canals in transparent resin blocks were instrumented with the 10 kinds of files, and the degree of canal transportation obtained by double exposure technique of photography was compared with the analysis by the finite element method. The results were as follows : 1. The stress of a file in a curved canal increased from the file body to the file tip. 2. The stress of a stainless steel file was about 2.5 times greater than that of a same-sized NiTi file. 3. The stress distributions of files of an identical material were the same, and the strain energies of files of an identical material increased as the size of files increased. 4. The strain energy of a No. 35 NiTi file was about the same as that of a No. 20 stainless steel file. 5. The degree of canal transportation by a stainless steel file was greater than that by a same-sized NiTi file. The degree of canal transportation generally increased as the size of a file increased. 6. The degree of canal transportation of a No. 35 NiTi file was about the same as that of a No. 20 stainless steel file.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.36-45
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• 1993

This paper presents a model and a heuristic procedure to design production planning and transportation scheduling systems of critical items, components and products on the basis of material requirement planning concept and transportation planning model. These systems are stemmed from a multi-site multi-product production company in a international economic zone. An example is provided to validate the heuristic procedure developed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1-8
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• 2006

This paper considers an interesting transportation problem where trailers and tractors are involved in moving material. We identified a class of combinatorial optimization problems for minimizing the number of tractors and trailers required to accommodate the transportation needs. Then, we show that the fundamental problem is NP-hard and analyze its properties to develop efficient heuristic to handle the problem effectively.